Reaction device for forming equipment

ABSTRACT

A reaction device for forming equipment includes a base, a reaction member movably spaced therefrom by guides, and a return gas spring carried by the base and operatively engaged to the reaction member for yieldably biasing the reaction member away from the base. The base has a return gas spring passage and guide shaft passages spaced apart therefrom. A return gas spring is received in the return gas spring passage of the base, and has a piston rod with an end arranged for contact with the reaction member. The guides include guide shafts arranged for engagement with the reaction member and disposed in guide bushings, which are received in the guide shaft passages of the base and preferably project below the base for use in locating the reaction device on the forming equipment.

FIELD OF THE INVENTION

This invention relates generally to forming equipment, and moreparticularly to a reaction device for use with forming equipment.

BACKGROUND OF THE INVENTION

Gas springs are commonly used in various implementations in formingequipment to provide a movable component of a forming die with ayielding force, which is maintained throughout normal travel of themovable component. For example, in a binder ring implementation, a gasspring provides a yielding force against a binder ring of a forming dieto hold a metal workpiece while another part of the forming die forms,cuts, stretches, or bends the workpiece. In a lifter implementation, thegas spring provides a yielding force to lift a workpiece off a surfaceof the forming die. In a cam tool implementation, the gas spring appliesa yielding force to return a cam-activated tool to its home position.

Conventional gas springs, such as those disclosed in U.S. Pat. Nos.5,275,387 and 5,303,906, typically have a piston rod disposed within agenerally hollow cylinder including a closed rear end with a fill valvedisposed therein, and a sealing assembly closing a forward open end ofthe cylinder and including a reinforcing or retaining ring and sealsbetween the rod and the cylinder. Thus, a sealed gas chamber is definedbetween a rear end of the piston rod and the inside of the cylinder. Thegas chamber receives a pressurized gas for yieldably biasing the pistonrod to an extended position and for yieldably resisting movement of thepiston rod from its extended position to a displaced or retractedposition within the cylinder.

For example, upon closure of forming dies toward one another, a force isexerted on the piston rod, which force immediately yields a resultantreactive force of the gas spring. As the piston rod is displaced intothe cylinder, the gas becomes further compressed. This gas compressionby the piston causes the gas volume to decrease and, in accordance withBoyle's law, increases the gas pressure and thereby increases theresultant reactive force imposed on the die. And, the greater the pistondisplacement, the greater the reactive force. The sealing arrangementsbetween the end cap and the cylinder, and between the piston rod and thecylinder prevents the release of the pressurized gas, thereby assuringthe rise in gas pressure within the chamber.

The gas springs are capable of handling compression loads that aresubstantially parallel to the piston rod, but are not capable ofresisting significant torque or side loading. Therefore, guide posts areoften attached to the forming die and on either side of the gas springto handle torque and side loading. Unfortunately, however, integrationof guide posts directly into a forming die alongside a gas springusually requires precious additional space on the forming die, costlycustomized design of the forming die and guide post assembly, and afixed stroke length of the gas spring.

SUMMARY OF THE INVENTION

A reaction device is relatively compact, of modular design, andpreferably available in different lengths or is otherwise adjustable instroke length for use in a variety of different applications withforming equipment. The reaction device includes a base, a reactionmember movably spaced from the base by guides, and a return gas springcarried by the base and operatively engaged to the reaction member foryieldably biasing the reaction member relatively away from the base. Thebase has a return gas spring passage and guide shaft passages spacedapart from the return gas spring passage. The return gas spring isreceived in the return gas spring passage of the base and has a pistonrod with an end arranged for contact with the reaction member. Theguides include guide bushings carried by the base and received in theguide shaft passages thereof, and at least one of the guide bushingspreferably has an end projecting below the base for use in locating thereaction device on the forming equipment, such as in doweling thereaction device to a forming machine. The guides also include guideshafts received in the guide bushings, and at least one of the guideshafts includes an end arranged for engagement with the reaction memberto movably support the reaction member with respect to the base.

According to a preferred aspect of the reaction device, the reactionmember includes guide shaft apertures having flat portions forengagement with corresponding flat portions of the ends of the guideshafts. According to another preferred aspect, the guide bushings arecarried by the base in an axially adjustable manner with retainingmembers therebetween. The guide bushings include a plurality of externalcircumferential grooves, the base includes a corresponding internalcircumferential groove within at least one of the guide shaft passages,and the retaining members are disposed between the base and the guidebushings.

At least some of the objects, features and advantages that may beachieved by at least some embodiments of the invention include providinga reaction device that is readily adaptable to various forming equipmentapplications including binder ring, lifter, and cam tool applications;maximizes guidance precision and load capacity while minimizing externaldimensions; provides a standardized design that can be “dropped in” toexisting forming machine or tool designs; is compact and easy torebuild; and is of relatively simple design and economical manufactureand assembly, rugged, durable, reliable and in service has a long usefullife.

Of course, other objects, features and advantages will be apparent inview of this disclosure to those skilled in the art. Various otherreaction devices embodying the invention may achieve more or less thanthe noted objects, features or advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will be apparent from the following detailed description ofthe preferred embodiments and best mode, appended claims, andaccompanying drawings in which:

FIG. 1 is a perspective cross-sectional view according to a presentlypreferred form of a reaction device for use with forming equipment;

FIG. 2 is a front cross-sectional view of the reaction device of FIG. 1;

FIG. 2A is an enlarged view of encircled portion 2A of the reactiondevice of FIG. 2;

FIG. 2B is an enlarged view of encircled portion 2B of the reactiondevice of FIG. 2;

FIG. 3 is a side cross-sectional view of the reaction device of FIG. 1,taken along line 3-3 of FIG. 2;

FIG. 4 is a perspective view of a reaction member of the reaction deviceof FIG. 1;

FIG. 5 is a side view of a guide shaft of the reaction device of FIG. 1;

FIG. 5A is an end view of the guide shaft of FIG. 5;

FIG. 6 is a partially sectioned side view of a presently preferred formof a guide bushing of the reaction device of FIG. 1; and

FIG. 7 is a side view of another preferred form of a guide bushingsuitable for use with the reaction device of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring in more detail to the drawings, FIGS. 1 through 3 illustrate areaction device 10 arranged for use with metal forming equipment F suchas a forming machine, tool, or die. The reaction device 10 may be usedwith the forming equipment F as a binder ring, workpiece lifter, camtool return, or the like. In general, the reaction device 10 includes abase 12 for mounting the device 10 to the forming equipment F, areaction member 14 that is movably carried by the base 12 by guidedevices 16 and that is yieldably disposed in an extended position by areturn gas spring 18. More guide devices 16 and/or return gas springs 18could be used, depending on the desired overall size and shape of thereaction device 10.

The base 12 mounts the device 10 to the forming equipment F and supportsthe other various components of the device 12, such as the guide devices16 and return gas spring 18. The base 12 may be a single plate componentor a multiple plate assembly as shown. Preferably, the base 12 is ofsandwich-like construction including a lower plate 20 for mountingagainst the forming equipment F and an upper plate 22 mounted againstthe lower plate 20. The plates 20, 22 may be fastened together withmachine screws 24 or other types of fasteners, and the entire base 12can be bolted in place to the forming equipment F. The base 12 ispreferably rectangular in shape and includes a centrally disposed returngas spring passage 26 therethrough for accepting the return gas spring18 therein. The base 12 further includes guide passages 28 therethroughon either side of the return gas spring passage 26 for accepting theguide devices 16 therein. The base 12 also includes bores 30 foraccepting recessed fasteners 32 such as cap screws, bolts, or othertypes of fasteners suitable for use in fastening the reaction device 10to the forming equipment F.

The forming equipment F includes relatively straightforward machiningpreparation to install the reaction device 10. Because of the lowprofile and flat lower plate 20 of the base 12, the forming equipment Fis preferably prepared with a machined flat surface S for engagementwith the base 12. Also, the forming equipment F is preferably preparedwith three precision drilled or bored holes H, P for accepting the guidedevices 16 and return gas spring 18, and with two outboard tapped holesT for fixing the reaction device 10 in place.

The return gas spring 18 may be any suitable device for yieldablybiasing the reaction member 14 in a direction away from the base 12, butis preferably a nitrogen gas spring adapted for mounting to the base 12within the return gas spring passage 26 thereof. The return gas spring18 also extends into a return gas spring passage P within the formingequipment F as shown in FIG. 2. Nitrogen gas springs are readilyavailable from the assignee hereof, such as the DADCO Micro Series,including the Micro C.090 line of products.

The return gas spring 18 shown in the drawing figures is a simplifiedschematic and, internally, may be constructed in accordance with U.S.Pat. Nos. 5,275,387 and 5,303,906, which patents are incorporated byreference herein in their entireties. The gas spring 18 may include ahousing or generally hollow cylinder 34 and a piston rod 36 disposedwithin the cylinder 34, wherein a sealed gas chamber 38 is definedbetween a cylinder end 40 of the piston rod 36 and a bottom 42 of thechamber 38 inside the cylinder 34. A closed rear end of the gas spring18 is preferably fitted with a fill valve (not shown) therethrough forreceiving pressurized gas from a remote source. At an opposite end ofthe gas spring 18, a reaction end 44 of the rod 36 is arranged forabutment or contact with the reaction member 14. Those of ordinary skillin the art will recognize that the housing or cylinder 34 need not becylindrical in shape but could be of any other suitable shapes.

The gas chamber 38 preferably retains a pressurized gas for biasing thepiston rod 36 to an extended position and for resisting movement of thepiston rod 36 from its extended position to a displaced or retractedposition in the cylinder 34. The gas spring 18 may be in fluidcommunication with a control panel (not shown) through a high pressurehose and fittings. The mini control panel is preferably a DADCO model #90.407.11 mini control panel, which is used to fill, drain, and monitorthe pressure of a plurality of gas springs that are linked either inseries or in parallel from outside of a die. The mini control panelincludes a high pressure gauge, a quick disconnect fill valve, a bleedvalve, and a rupture disk to prevent over-pressurization of the gassprings. This arrangement enables common pressurization or activation ofa group of multiple or tandem reaction devices that are all attached toa common structural member on the forming equipment. Accordingly, thegroup of reaction devices may be actuated simultaneously from thecontrol panel. Also, if a gas spring of one of the reaction devicessupporting the common structure is overpowered or fails, then the othergas springs of the other reaction devices share the load previouslycarried by the failed reaction device to prevent or reduce the liklihoodof damage to the forming equipment.

The return gas spring 18 is preferably carried by the base 12 using asplit-type mounting configuration. Accordingly, the cylinder 34 of thereturn gas spring 18 includes at least one external circumferentialgroove 46, and may have two or more axially spaced apart circumferentialgrooves 46, and the base 12 includes a corresponding internalcircumferential groove 48, wherein a retaining member 50 is mutuallydisposed in groove 48 and one of the grooves 46 for retaining the returngas spring 18 in the base 12. As used herein, the term groove includesany generally circumferential or annular channel or depression andencompasses open counterbores, closed channels, and the like.

Any suitable types of retaining members may be used and, for example,may be circumferentially continuous or interrupted, and of round orrectangular cross-section. More specifically, the retaining members maybe outer diameter wire snap rings, round wire split rings, flat spiraltype snap rings, or the like. In any case, the internal circumferentialgroove 48 in the base 12 is preferably formed as a face groove in thelower plate 20 of the base 12, and coaxially disposed with respect tothe return gas spring passage 26. Also, before the upper plate 22 ismounted to the lower plate 20, it is preferred that the retaining member50 is first assembled within the groove 46 of the return gas springcylinder 34, which is then assembled into the return gas spring passage26 of the lower plate 20 portion of the base 12 until the retainingmember 50 seats in the groove 48 in the lower plate 20 of the base 12.

The guide devices 16 preferably include guide bushings 52 retainedwithin the guide shaft passages 28 of the base 12 and carried by thebase 12, and guide shafts 54 received in the guide bushings 52. But theguide devices 16 may be any suitable individual component or combinationof components for movably attaching the reaction member 14 to the base12 and locating the base 12 to a forming machine. For example, the guidebushings 52 could be omitted wherein the guide shafts 54 would bereceived directly within the respective guide shaft passages 28 of thebase 12. In such a case, it would be desirable to plate the steel base12 with a coating, such as nickel-Teflon, on the guide shaft passages28, or the base 12 could be composed of iron or a copper alloy.

The guide bushings 52 are preferably substantially cylindrical, solid,one-piece components, for example composed of bronze. Or, asalternatively shown at numeral 152 in FIG. 2, the bushings 52 may bemultiple-piece components including a metal sleeve 151 or housing withone or more thin-walled bushing rings 153 press fit therein andpreferably composed of steel and brass. The bushings 152 are not shownin correct position, and are shown for exemplary purposes only. Also,the bushings 52, 152 may be pre-lubricated, such as with graphite plugsor grooves or impregnated with lubricant.

In any case, the bushings 52 preferably have lower ends 56 that projectbelow the lower plate 20 of the base 12 and into the guide passages H inthe forming equipment F for use as doweling devices in locating thereaction device 10 to the forming equipment F. The bushings 52 mayextend any suitable distance below the base 12 so as to suitably engagethe forming equipment F, but preferably extend about three to sevenmillimeters or more. Accordingly, the guide passages 28 in the base 12,the outer diameter of the bushings 52, and the guide passages H in theforming equipment F are preferably precision machined. This dual use ofthe bushings 52 as guiding devices and as dowels eliminates the need forother doweling of the base 12 to the forming equipment F. Adding extradowel pins and holes to the base 12 would make the reaction device 10unnecessarily wider or longer. Thus, the construction and assembly ofthe reaction device 10 is kept simple and its packaging envelope ismaintained as small as possible.

Referring to FIGS. 2, 2A, 2B, and 6, the guide bushings 52 arepreferably retained in the base 12 in a similar fashion as the returngas spring 18, using a split-type mounting configuration. The outerdiameter of each bushing 52 may be precision ground and include one ormore external circumferential grooves 58. Also, the base 12 includes acorresponding internal circumferential groove 60 concentric with thepassage 28, wherein a retaining member 62 is mutually disposed in thegrooves 60 and one of the grooves 58 for retaining the bushings 52 inthe base 12. Preferably, the internal circumferential groove 60 isformed as a face groove in the lower plate 20 of the base 12, andcoaxially with respect to the bushing passage 28. Also, before the upperplate 22 is mounted to the lower plate 20, it is preferred that theretaining member 62 is first assembled within one of the grooves 58 ofthe bushing 52, which is then assembled into the bushing passage 28 ofthe lower plate 20 until the retaining member 62 seats in the groove 60in the lower plate 20.

In another bushing configuration, as shown in FIG. 7, a guide bushing252 may be used that includes holes 255 extending radially ortransversely therethrough, and external circumferential grooves 258therein. The grooves 258 are provided so that the bushings 252 may becarried by the base in an axially adjustable manner to enable axial orstroke adjustments in the reaction device 10. In other words, thebushings 252 may be fastened to the base 12 using, for example, lowergrooves thereof for maximum stroke or distance between the reactionmember 14 and base 12. Or the bushings 252 may be fastened to the base12 using upper grooves for minimum stroke of the reaction member 14 andgreater preload on the return gas spring 18.

The guide shafts 54 of the guide devices 16 are substantiallycylindrical and include base ends 64 that are inserted within the guidebushings 52. Guide stops 66 retain the movable guide shafts 64 in thebase 12, are attached to the base ends 64 of the guide shafts 54, andinclude a resilient cushion 68 sandwiched between a cushion spacer orwasher 70 and a head 72 of a guide stop shoulder screw 74 threadablyreceived in the guide shaft. The cushion 68 may be composed of acomposite material or a polymer such as urethane, and the cushion washer70 may be composed of any suitable material including brass or steel.The cushioned guide stops 66 enable deceleration and dampening of themomentum of the moving guide rods 54, reaction member 14, and anythingthat may be mounted to the reaction member 14 when the reaction member14 reaches the end of the stroke defined by the guide rods 54 and, thus,comes to a stop.

This cushioning action enables a reduction in stresses on the reactionmember 14 and yields more controlled extension of the reaction member14. The reaction device load capacity may be determined based on maximumcyclical stresses and the speed at which the mass on the reaction member14 should decelerate. The shoulder screw 74 may be used to pre-load thecushion 68 if desired, and enables use of pre-ground shaft material forthe guide posts 54, instead of forged or cast shafts or the like. Unlikesome conventional designs, the cushion 68 cannot ride up the guideshafts 54 when the reaction device 10 is compressed.

The reaction device 10 may also be rendered adjustable in stroke lengthby using additional precision spacers or washers 70 between the cushion68 and the ends 64 of the guide shafts 54. The additional washers wouldbe matched pairs to provide precision stroke length adjustment for bothguides. As shown, a single washer 70 acts as a “zero” or baseline spacerand adding washers, and/or replacing the washer 70 with washers ofdifferent thickness, would enable the stroke of the reaction device 10to be adjusted to desired travel specifications without having toprovide a special adjustable stroke length gas spring.

Opposite of the base ends 64, the guide shafts 54 include reaction ends76 that are fastened to the reaction member 14 by recessed fasteners 78such as machine screws, bolts, or other types of fasteners. As bettershown in FIGS. 5 and 5 a, the guide shaft reaction ends 76 include areduced diameter portion having opposed flats 80 for keyed engagementwith the reaction member 14 as will be described herein below.

Referring to FIGS. 1 and 2, the reaction member 14 may be a steel plate,sub-plate, or the like, for supporting other components or devices. Thereaction member 14 is spaced apart from the base 12 by the movable guideshafts 54 and, thus, is movable toward and away from the base 12. Thereaction member 14 includes spaced apart guide shaft apertures 82 forreceiving the reaction ends 76 of the guide shafts 54, and anintermediate section 84 between the plurality of guide shaft apertures82 for cooperation with the reaction end 44 of the return gas springpiston rod 36.

As better shown in FIG. 4, the guide shaft apertures 82 are preferablycounterbored to include oblong recesses or counterbores 86. The oblongcounterbores 86 preferably each include opposed rounded ends 88 thatengage the corresponding diameter of the reaction ends 76 of the guideshafts 54 and opposed flat sides 90 that correspond to the flats 80 ofthe reaction ends 76 of the guide shafts 54. Accordingly, the flats 76on the guide shafts 54 and the flats 90 of the reaction member 14 engageto prevent rotation of the guide shafts 54 relative to the reactionmember 14. With this construction, the guide shafts 54 do not need to beprovided with wrench flats. Wrench flats are conventionally required forservice or assembly and tend to reduce the effective bearing area ofassociated guide shafts. With this reaction device 10, however, thekeyed engagement between the guide shafts 54 and the reaction member 14eliminates the need for wrench flats and provides maximized guide shaftbearing area for a given distance between the reaction member 14 andbase 12.

The reaction member 14 may include various other features, such asthreaded holes, dowel holes, and the like, to enable various desireduses of the reaction member 14. For example, the reaction member, orsome tool mounted thereto, may be used as a binder to clamp down on aworkpiece during forming thereof, a lifter plate for lifting a workpieceafter forming thereof, a cam return member for returning a cam toolafter a forming operation on a workpiece, or the like.

In operation, the reaction device 14 is normally in its fully extendedstate, wherein the piston rod 36 of the return gas spring 18 is fullyadvanced. In the fully extended state, the guide shafts 54 are fullydisplaced until the guide stops 66 are located against the lower ends 56of the guide bushings 52 such that the distance between the reactionmember 14 and base 12 is maximized. In contrast, the reaction device 10may be displaced to its fully compressed state, wherein the reactiondevice 10 reacts to some movement of some mechanism of the formingequipment F to which the reaction device 10 is mounted. For example, anupper ram or platen (not shown) of a forming press may advance toward,then contact, and ultimately displace the reaction member 14 in adirection toward the base 12. Thereafter, when the upper platen of theforming press retracts away from and ultimately disengages the reactiondevice 10, the reaction device 10 returns to its state of rest under itsown power of its return gas spring 18, wherein the piston rod 36advances and displaces the reaction member 14 away from the base 12until the guide stops 66 engage the bushings 52. As shown, the reactiondevice 10 is slightly displaced from its fully extended position towardits retracted position, such that the guide stops 66 are spaced awayfrom the lower ends 56 of the bushings 52.

As best illustrated by FIGS. 2 and 3, the overall envelope of thereaction device 10 is minimized relative to the guiding precision andload capacity of the reaction device 10. In other words, the operationalstiffness and smoothness of the reaction device 10 is high in proportionto the width and thickness of the base 12 and reaction member 14. Asjust one example, 16 mm diameter guide shafts may be used for a 25 mmwide reaction member. Similarly, a 19 mm diameter return gas spring maybe used with a 26 mm thick base. These dimensions are merelyillustrative of the compact packaging achievable with the design of thepresent reaction device 10, and are not to be construed as limitationsof the claimed reaction device.

As used in this specification and claims, the terms “for example,” “forinstance,” and “such as,” and the verbs “comprising,” “having,”“including,” and their other verb forms, when used in conjunction with alisting of one or more components or other items, are each to beconstrued as open-ended, meaning that that the listing is not to beconsidered as excluding other or additional components, elements, oritems. Moreover, directional words such as top, bottom, upper, lower,radial, circumferential, axial, lateral, longitudinal, vertical,horizontal, and the like are employed by way of description and notlimitation. Other terms are to be construed using their broadestreasonable meaning unless they are used in a context that requires adifferent interpretation. When introducing elements of the presentinvention or the embodiments thereof, the articles “a,” “an,” “the,” and“said” are intended to mean that there are one or more of the elements.

It is to be understood that the invention is not limited to theparticular exemplary embodiments disclosed herein, but rather is definedby the claims below. In other words, the statements contained in theforegoing description relate to particular exemplary embodiments and arenot to be construed as limitations on the scope of the invention asclaimed below or on the definition of terms used in the claims, exceptwhere a term or phrase is expressly defined above.

Although the present invention has been disclosed in conjunction with alimited number of presently preferred exemplary embodiments, many othersare possible and it is not intended herein to mention all of thepossible equivalent forms and ramifications of the present invention.Other modifications, variations, forms, ramifications, substitutions,and/or equivalents will become apparent or readily suggest themselves topersons of ordinary skill in the art in view of the foregoingdescription. In other words, the teachings of the present inventionencompass many reasonable substitutions or equivalents of limitationsrecited in the following claims. As just one example, the disclosedstructure, materials, sizes, shapes, and the like could be readilymodified or substituted with other similar structure, materials, sizes,shapes, and the like. In another example, the invention has beendisclosed in conjunction with metal forming equipment. However,additional applications are contemplated for the reaction device, suchas in injection molding equipment, plastic sheet molding equipment, orany other suitable machine applications where it is desirable to use areaction device, and all can be provided without departing from thedisclosure. Indeed, the present invention is intended to embrace allsuch forms, ramifications, modifications, variations, substitutions,and/or equivalents as fall within the spirit and broad scope of thefollowing claims.

1. A reaction device for use with forming equipment, comprising: a basehaving a return spring passage, and at least two guide shaft passageseach spaced apart from the return spring passage; a reaction memberspaced apart from the base; a return spring received in the returnspring passage of the base and carried by the base, the return springhaving a rod with an end arranged for contact with the reaction member;a guide bushing received in each guide shaft passage of the base andcarried by the base, at least one of the guide bushings having an endprojecting below the base for use in locating the reaction device on theforming equipment; and a guide shaft received in each guide bushing, andat least one guide shaft having an end arranged for engagement with thereaction member.
 2. The reaction device of claim 1, wherein the reactionmember includes at least two guide shaft apertures, at least one of theguide shaft apertures includes a flat portion and an end of at least oneof the guide shafts includes a corresponding flat portion for engagementwith the flat portion of the reaction member.
 3. The reaction device ofclaim 1, wherein at least one of the guide bushings is carried by thebase with a retaining member therebetween, such that the at least oneguide bushing includes at least one external circumferential groove, thebase includes a corresponding internal circumferential groove in atleast one of the guide shaft passages, and the retaining member ismutually disposed in the grooves.
 4. The reaction device of claim 3,wherein the base includes an upper plate and a lower plate, and thecorresponding internal circumferential groove is in at least one of theupper and lower plates.
 5. The reaction device of claim 3, wherein theat least one guide bushing has at least two spaced apart externalcircumferential grooves to allow stroke adjustment of the reactiondevice.
 6. The reaction device of claim 1, wherein the return spring iscarried by the base with a retaining member disposed therebetween, suchthat the return spring includes at least one external circumferentialgroove, the base includes a corresponding internal circumferentialgroove in the return spring passage, and a retaining member is mutuallydisposed in the grooves.
 7. The reaction device of claim 1, wherein theat least one guide bushing is carried by the base in an axiallyadjustable manner.
 8. The reaction device of claim 7, wherein the atleast one guide bushing includes at least two spaced apart externalcircumferential grooves, the base includes a corresponding internalcircumferential groove in at least one of the guide shaft passages, anda retaining member is mutually disposed in the grooves.
 9. A reactiondevice for use with forming equipment, comprising: a base having areturn gas spring passage, and at least two guide shaft passages eachspaced apart from the return gas spring passage; a reaction memberspaced apart from the base and including at least two guide shaftapertures and an intermediate section between the guide shaft apertures,wherein at least one of the guide shaft apertures includes a flatportion; a return gas spring received in the return gas spring passageof the base and carried by the base, the return gas spring having apiston rod with an end arranged for contact with the intermediatesection of the reaction member; a guide bushing received in each guideshaft passage of the base, at least one guide bushing having an endprojecting below the base for use in locating the reaction device on theforming equipment, the at least one guide bushing having at least oneexternal circumferential groove, the base having a correspondinginternal circumferential groove in at least one of the guide shaftpassages, and a retaining member being mutually disposed in the grooves;and a guide shaft received in each guide bushing, at least one of theguide shafts including an end arranged for engagement with the reactionmember in at least one of the guide shaft apertures thereof, wherein theend of the at least one guide shaft includes a corresponding flatportion for engagement with the flat portion of the reaction member. 10.The reaction device of claim 9, wherein the return gas spring includesat least one external circumferential groove, the base includes acorresponding internal circumferential groove in the return gas springpassage, and a retaining member is mutually disposed in the grooves. 11.The reaction device of claim 9, wherein the at least one guide bushingincludes at least two spaced apart external circumferential grooves toallow stroke adjustment of the reaction device.
 12. The reaction deviceof claim 11, wherein the base includes an upper plate and a lower plate,and the corresponding internal circumferential groove is in at least oneof the upper and lower plates.
 13. The reaction device of claim 12,wherein the at least one guide bushing includes three spaced apartexternal circumferential grooves.
 14. The reaction device of claim 9,wherein the return gas spring includes a cylinder carrying the pistonrod and having at least one external circumferential groove, the baseincludes a corresponding internal circumferential groove in the returngas spring passage, and a retaining member is mutually disposed in thegrooves.
 15. The reaction device of claim 9, wherein the at least oneguide bushing is carried by the base in an axially adjustable manner.16. The reaction device of claim 15, wherein the at least one guidebushing has at least two spaced apart external circumferential grooves,the base includes a corresponding internal circumferential groove in atleast one of the guide shaft passages, and a retaining member ismutually disposed in the grooves.
 17. A reaction device for use withforming equipment, comprising: a base including an upper plate and alower plate, and having a return gas spring passage and at least twoguide shaft passages each spaced apart from the return gas springpassage; a reaction member spaced apart from the base and including atleast two guide shaft apertures and an intermediate section between theguide shaft apertures, wherein at least one of the guide shaft aperturesincludes a flat portion; a return gas spring received in the return gasspring passage of the base and carried by the base, the return gasspring having a piston rod with an end arranged for contact with theintermediate section of the reaction member; a guide bushing received ineach guide shaft passage of the base, the guide bushings having an endprojecting below the base for use in locating the reaction device on theforming equipment, the guide bushings having at least two externalcircumferential grooves to allow stroke adjustment of the reactiondevice, the base having a corresponding internal circumferential groovein at least one of the guide shaft passages, and a retaining memberbeing mutually disposed in the grooves; and a guide shaft received ineach of the guide bushings, at least one of guide shafts including anend arranged for engagement with the reaction member in one of the guideshaft apertures thereof, wherein the end of the at least one guide shaftincludes a corresponding flat portion for engagement with the flatportion of the reaction member.
 18. The reaction device of claim 17,wherein the return gas spring includes at least one externalcircumferential groove, the base includes a corresponding internalcircumferential groove in the return gas spring passage, and a retainingmember is mutually disposed in the grooves.
 19. A reaction device foruse with forming equipment, comprising: a base having a return springpassage, and at least two guide shaft passages each spaced apart fromthe return spring passage; a reaction member spaced apart from the baseand including at least two guide shaft apertures and an intermediatesection between the guide shaft apertures, wherein at least one of theguide shaft apertures includes a flat portion; a return spring receivedin the return spring passage of the base and carried by the base, thereturn spring having a piston rod with an end arranged for contact withthe intermediate section of the reaction member; and a guide shaftreceived in each guide shaft passage, at least one of the guide shaftsincluding an end arranged for engagement with the reaction member in atleast one of the guide shaft apertures thereof, wherein the end of theat least one guide shaft includes a corresponding flat portion forengagement with the flat portion of the reaction member.
 20. Thereaction device of claim 19, further comprising: a guide bushingreceived in each guide shaft passage of the base, the guide bushingshaving ends projecting below the base for use in locating the reactiondevice on the forming equipment, wherein the guide shafts are receivedin the guide bushings.
 21. The reaction device of claim 19, furthercomprising: a guide stop attached to each end of the guide shafts toretain the guide shafts in the base, and including a resilient cushionsandwiched between at least one cushion washer and a head of a guidestop shoulder screw fastened to its respective guide shaft end.
 22. Thereaction device of claim 21, wherein the thickness of the at least onecushion washer is selective to enable adjustment in the stroke length ofthe reaction device.